mirror of
https://github.com/golang/go
synced 2024-11-24 23:57:57 -07:00
196b663075
To allow these types as map keys, we must fill in equal and hash functions in their algorithm tables. Structs or arrays that are "just memory", like [2]int, can and do continue to use the AMEM algorithm. Structs or arrays that contain special values like strings or interface values use generated functions for both equal and hash. The runtime helper func runtime.equal(t, x, y) bool handles the general equality case for x == y and calls out to the equal implementation in the algorithm table. For short values (<= 4 struct fields or array elements), the sequence of elementwise comparisons is inlined instead of calling runtime.equal. R=ken, mpimenov CC=golang-dev https://golang.org/cl/5451105
400 lines
6.3 KiB
Go
400 lines
6.3 KiB
Go
// $G $D/$F.go && $L $F.$A && ./$A.out
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import "unsafe"
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func use(bool) {}
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func stringptr(s string) uintptr { return *(*uintptr)(unsafe.Pointer(&s)) }
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func isfalse(b bool) {
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if b {
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// stack will explain where
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panic("wanted false, got true")
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}
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}
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func istrue(b bool) {
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if !b {
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// stack will explain where
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panic("wanted true, got false")
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}
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}
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type T *int
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func main() {
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var a []int
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var b map[string]int
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var c string = "hello"
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var d string = "hel" // try to get different pointer
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d = d + "lo"
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if stringptr(c) == stringptr(d) {
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panic("compiler too smart -- got same string")
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}
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var e = make(chan int)
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var ia interface{} = a
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var ib interface{} = b
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var ic interface{} = c
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var id interface{} = d
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var ie interface{} = e
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// these comparisons are okay because
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// string compare is okay and the others
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// are comparisons where the types differ.
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isfalse(ia == ib)
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isfalse(ia == ic)
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isfalse(ia == id)
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isfalse(ib == ic)
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isfalse(ib == id)
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istrue(ic == id)
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istrue(ie == ie)
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istrue(ia != ib)
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istrue(ia != ic)
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istrue(ia != id)
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istrue(ib != ic)
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istrue(ib != id)
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isfalse(ic != id)
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isfalse(ie != ie)
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// these are not okay, because there is no comparison on slices or maps.
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//isfalse(a == ib)
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//isfalse(a == ic)
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//isfalse(a == id)
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//isfalse(b == ic)
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//isfalse(b == id)
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istrue(c == id)
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istrue(e == ie)
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//isfalse(ia == b)
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isfalse(ia == c)
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isfalse(ia == d)
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isfalse(ib == c)
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isfalse(ib == d)
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istrue(ic == d)
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istrue(ie == e)
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//istrue(a != ib)
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//istrue(a != ic)
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//istrue(a != id)
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//istrue(b != ic)
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//istrue(b != id)
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isfalse(c != id)
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isfalse(e != ie)
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//istrue(ia != b)
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istrue(ia != c)
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istrue(ia != d)
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istrue(ib != c)
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istrue(ib != d)
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isfalse(ic != d)
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isfalse(ie != e)
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// 6g used to let this go through as true.
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var g uint64 = 123
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var h int64 = 123
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var ig interface{} = g
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var ih interface{} = h
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isfalse(ig == ih)
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istrue(ig != ih)
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// map of interface should use == on interface values,
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// not memory.
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var m = make(map[interface{}]int)
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m[ic] = 1
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m[id] = 2
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if m[c] != 2 {
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println("m[c] = ", m[c])
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panic("bad m[c]")
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}
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// non-interface comparisons
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{
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c := make(chan int)
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c1 := (<-chan int)(c)
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c2 := (chan<- int)(c)
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istrue(c == c1)
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istrue(c == c2)
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istrue(c1 == c)
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istrue(c2 == c)
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isfalse(c != c1)
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isfalse(c != c2)
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isfalse(c1 != c)
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isfalse(c2 != c)
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d := make(chan int)
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isfalse(c == d)
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isfalse(d == c)
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isfalse(d == c1)
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isfalse(d == c2)
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isfalse(c1 == d)
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isfalse(c2 == d)
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istrue(c != d)
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istrue(d != c)
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istrue(d != c1)
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istrue(d != c2)
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istrue(c1 != d)
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istrue(c2 != d)
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}
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// named types vs not
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{
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var x = new(int)
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var y T
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var z T = x
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isfalse(x == y)
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istrue(x == z)
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isfalse(y == z)
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isfalse(y == x)
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istrue(z == x)
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isfalse(z == y)
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istrue(x != y)
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isfalse(x != z)
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istrue(y != z)
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istrue(y != x)
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isfalse(z != x)
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istrue(z != y)
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}
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// structs
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{
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var x = struct {
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x int
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y string
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}{1, "hi"}
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var y = struct {
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x int
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y string
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}{2, "bye"}
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var z = struct {
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x int
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y string
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}{1, "hi"}
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isfalse(x == y)
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isfalse(y == x)
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isfalse(y == z)
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isfalse(z == y)
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istrue(x == z)
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istrue(z == x)
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istrue(x != y)
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istrue(y != x)
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istrue(y != z)
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istrue(z != y)
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isfalse(x != z)
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isfalse(z != x)
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var m = make(map[struct {
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x int
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y string
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}]int)
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m[x] = 10
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m[y] = 20
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m[z] = 30
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istrue(m[x] == 30)
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istrue(m[y] == 20)
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istrue(m[z] == 30)
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istrue(m[x] != 10)
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isfalse(m[x] != 30)
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isfalse(m[y] != 20)
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isfalse(m[z] != 30)
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isfalse(m[x] == 10)
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var m1 = make(map[struct {
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x int
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y string
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}]struct {
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x int
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y string
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})
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m1[x] = x
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m1[y] = y
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m1[z] = z
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istrue(m1[x] == z)
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istrue(m1[y] == y)
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istrue(m1[z] == z)
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istrue(m1[x] == x)
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isfalse(m1[x] != z)
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isfalse(m1[y] != y)
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isfalse(m1[z] != z)
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isfalse(m1[x] != x)
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var ix, iy, iz interface{} = x, y, z
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isfalse(ix == iy)
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isfalse(iy == ix)
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isfalse(iy == iz)
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isfalse(iz == iy)
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istrue(ix == iz)
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istrue(iz == ix)
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isfalse(x == iy)
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isfalse(y == ix)
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isfalse(y == iz)
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isfalse(z == iy)
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istrue(x == iz)
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istrue(z == ix)
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isfalse(ix == y)
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isfalse(iy == x)
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isfalse(iy == z)
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isfalse(iz == y)
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istrue(ix == z)
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istrue(iz == x)
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istrue(ix != iy)
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istrue(iy != ix)
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istrue(iy != iz)
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istrue(iz != iy)
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isfalse(ix != iz)
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isfalse(iz != ix)
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istrue(x != iy)
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istrue(y != ix)
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istrue(y != iz)
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istrue(z != iy)
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isfalse(x != iz)
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isfalse(z != ix)
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istrue(ix != y)
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istrue(iy != x)
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istrue(iy != z)
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istrue(iz != y)
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isfalse(ix != z)
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isfalse(iz != x)
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}
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// arrays
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{
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var x = [2]string{"1", "hi"}
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var y = [2]string{"2", "bye"}
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var z = [2]string{"1", "hi"}
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isfalse(x == y)
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isfalse(y == x)
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isfalse(y == z)
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isfalse(z == y)
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istrue(x == z)
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istrue(z == x)
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istrue(x != y)
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istrue(y != x)
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istrue(y != z)
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istrue(z != y)
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isfalse(x != z)
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isfalse(z != x)
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var m = make(map[[2]string]int)
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m[x] = 10
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m[y] = 20
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m[z] = 30
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istrue(m[x] == 30)
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istrue(m[y] == 20)
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istrue(m[z] == 30)
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isfalse(m[x] != 30)
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isfalse(m[y] != 20)
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isfalse(m[z] != 30)
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var ix, iy, iz interface{} = x, y, z
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isfalse(ix == iy)
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isfalse(iy == ix)
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isfalse(iy == iz)
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isfalse(iz == iy)
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istrue(ix == iz)
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istrue(iz == ix)
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isfalse(x == iy)
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isfalse(y == ix)
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isfalse(y == iz)
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isfalse(z == iy)
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istrue(x == iz)
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istrue(z == ix)
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isfalse(ix == y)
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isfalse(iy == x)
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isfalse(iy == z)
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isfalse(iz == y)
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istrue(ix == z)
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istrue(iz == x)
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istrue(ix != iy)
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istrue(iy != ix)
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istrue(iy != iz)
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istrue(iz != iy)
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isfalse(ix != iz)
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isfalse(iz != ix)
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istrue(x != iy)
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istrue(y != ix)
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istrue(y != iz)
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istrue(z != iy)
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isfalse(x != iz)
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isfalse(z != ix)
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istrue(ix != y)
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istrue(iy != x)
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istrue(iy != z)
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istrue(iz != y)
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isfalse(ix != z)
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isfalse(iz != x)
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}
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shouldPanic(p1)
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shouldPanic(p2)
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shouldPanic(p3)
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shouldPanic(p4)
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}
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func p1() {
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var a []int
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var ia interface{} = a
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use(ia == ia)
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}
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func p2() {
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var b []int
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var ib interface{} = b
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use(ib == ib)
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}
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func p3() {
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var a []int
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var ia interface{} = a
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var m = make(map[interface{}]int)
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m[ia] = 1
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}
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func p4() {
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var b []int
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var ib interface{} = b
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var m = make(map[interface{}]int)
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m[ib] = 1
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}
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func shouldPanic(f func()) {
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defer func() {
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if recover() == nil {
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panic("function should panic")
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}
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}()
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f()
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}
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